The March 13 special election in the Pennsylvania 18th congressional district in the southwestern part of the state should be a ho-hum affair.

It won’t be!

It should be ho-hum because it is a strongly Republican leaning district, rated a plus 11 Advantage Republican by the respected Cook report, and rated at least “ likely Republican” by virtually every other election handicapper.

Conventional wisdom favors Republicans so strongly because of the history and demographic make-up of the district. The now disgraced previous incumbent, Tim Murphy regularly won the district by 60 percent or more – while Hillary Clinton pulled only a miserly 38 percent in the 2016 presidential race.

What makes the district so favorable to Republicans is the composition of the electorate, which includes the southern portion of Allegheny County, as well as Washington, Westmoreland and Greene counties. The latter three were overwhelmingly carried by Trump in 2016. These counties are the homes of a substantial number of white, rural and small-town voters – many of them working class – the same voters that propelled Trump to his 44,000-vote statewide victory. They were a critical part of the president’s rust belt strategy, especially in the old manufacturing and mill town portions of the district.

The 18th is quintessentially Trump country.

But there are at least six compelling forces playing out in this race that should frighten Republicans and reassure Democrats as the latter try to pick up a “safe” GOP seat heading into the momentous 2018 Midterms.

The Political Climate –The national political climate has turned sharply against Republican candidates. Particularly worrisome is the so-called generic ballot question pollsters ask regarding which party voters prefer in the next congressional election. Democrats now sport a + 12.8 advantage in the Real Clear Politics average on that question, a statistic previously associated with massive “wave” elections sweeping incumbents out of power.

The Candidates —Democrats have nominated a centrist, former assistant U. S. Attorney, Conor Lamb, the scion of a respected area political family, who will campaign on issues like opioids and infrastructure. He has already moved to mute controversy over polarizing issues such as gun control and abortion. Republicans, however, have nominated a conservative firebrand, Rick Saccone, best known for introducing legislation requiring school districts to post “ in God we Trust” in every school. Saccone frequently brags “I was Trump before Trump was Trump” – while Trump’s approval rating in Pennsylvania sags at around 37 percent.

Lamb’s Union support- In an important union district with around 87,000 union members and families living in the 18th, union leadership support matters. The AFL-CIO has endorsed Lamb. Unions are expected to provide him strong support, including contributions and vigorous get out the vote efforts that are often key in special elections. While Murphy sometimes worked with unions, Saccone recently angered them by voting for a paycheck protection bill.

The GOP’s enthusiasm Gap –Increasingly in the aftermath of Trump’s controversial first year, Democrats are animated and activated while Republicans show less excitement and less enthusiasm. Some of this is playing out in the Democrats consistent “over performance” in earlier special elections around the country – not least the Democratic upset victory in Alabama. Republican candidates in every special election this year have failed to match Trump’s 2016 numbers. Then, too, Democrats seem genuinely excited about their nominee, whose resume and policy positions paint him as a moderate Democrat.

The Mid-term Curse – Incumbent presidents lose House seats in mid-term years, typically often a lot of them. And early as it is, the March special election is really the first mid-term in 2018. The history of incumbent losses goes back to Roosevelt and earlier. And few if any presidents have been less popular during midterms than Trump is likely to be. The real question for Republicans is not whether they lose House seats, but how many. The early March results will be an important clue to that.

The Wild Card – Democrats have some 70, 000 more registered voters in the district despite its GOP recent leanings. The enthusiasm gap mentioned earlier may bring some of these voters to the polls. But the true wild card is the current lawsuits challenging the fairness of the congressional districts the state legislature drew. It is possible that the actual March election might feature a re-configured 18th district more favorable to the Democrats.